From e7f180dcd8ab48f18b20d7e8a7e9b39192bdf8e0 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 10 Mar 2015 07:06:24 +0100 Subject: [PATCH] x86/fpu: Change xstateregs_get()/set() to use ->xsave.i387 rather than ->fxsave This is a cosmetic change: xstateregs_get() and xstateregs_set() abuse ->fxsave to access xsave->i387.sw_reserved. This practice is correct, ->fxsave and xsave->i387 share the same memory, but IMHO this looks confusing. And we can make this code more readable if we add a "struct xsave_struct *" local variable as well. Signed-off-by: Oleg Nesterov Signed-off-by: Borislav Petkov Reviewed-by: Rik van Riel Cc: Andy Lutomirski Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Tavis Ormandy Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1425967585-4725-1-git-send-email-bp@alien8.de Link: http://lkml.kernel.org/r/20150302183237.GB23085@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/i387.c | 25 +++++++++---------------- 1 file changed, 9 insertions(+), 16 deletions(-) diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 8416b5f85806..03cc0add8694 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -339,6 +339,7 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf) { + struct xsave_struct *xsave = &target->thread.fpu.state->xsave; int ret; if (!cpu_has_xsave) @@ -353,14 +354,12 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset, * memory layout in the thread struct, so that we can copy the entire * xstateregs to the user using one user_regset_copyout(). */ - memcpy(&target->thread.fpu.state->fxsave.sw_reserved, - xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes)); - + memcpy(&xsave->i387.sw_reserved, + xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes)); /* * Copy the xstate memory layout. */ - ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, - &target->thread.fpu.state->xsave, 0, -1); + ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, xsave, 0, -1); return ret; } @@ -368,8 +367,8 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { + struct xsave_struct *xsave = &target->thread.fpu.state->xsave; int ret; - struct xsave_hdr_struct *xsave_hdr; if (!cpu_has_xsave) return -ENODEV; @@ -378,22 +377,16 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset, if (ret) return ret; - ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, - &target->thread.fpu.state->xsave, 0, -1); - + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1); /* * mxcsr reserved bits must be masked to zero for security reasons. */ - target->thread.fpu.state->fxsave.mxcsr &= mxcsr_feature_mask; - - xsave_hdr = &target->thread.fpu.state->xsave.xsave_hdr; - - xsave_hdr->xstate_bv &= pcntxt_mask; + xsave->i387.mxcsr &= mxcsr_feature_mask; + xsave->xsave_hdr.xstate_bv &= pcntxt_mask; /* * These bits must be zero. */ - memset(xsave_hdr->reserved, 0, 48); - + memset(&xsave->xsave_hdr.reserved, 0, 48); return ret; }